International Conference on High-Power Particle Beams 

About: International Conference on High-Power Particle Beams is an academic conference. The conference publishes majorly in the area(s): Plasma & Beam (structure). Over the lifetime, 1112 publications have been published by the conference receiving 3027 citations.

Generation of subnanosecond microwave pulses by intense electron bunches moving in a periodic backward wave structure in the superradiative regime

Abstract: In this paper results of the experimental investigation of superradiance of intense subnanosecond electron bunches moving through a periodic waveguide structure and interacting with a backward propagating wave are presented.

Electron beam diodes using ferroelectric cathodes

Abstract: A new high current density electron source is investigated The source consists of a polarized ceramic disk with aluminium electrodes coated on both faces The front electrode is etched in a periodic grid to expose the ceramic beneath A rapid change in the polarization state of the ceramic results in the emission of a high density electron cloud into a 1 to 10mm diode gap The anode potential is maintained by a charged transmission line Some of the emitted electrons traverse the gap and an electron current flows The emitted electron current has been measured as a function of the gap spacing and the anode potential Current densities in excess of 70 A/cm2 have been measured The current is found to vary linearly with the anode voltage for gaps < 10 mm, and exceeds the Child-Langmuir current by at least two orders of magnitude The experimental data will be compared with predictions from a model based on the emission of a cloud of electrons from the ferroelectric which in turn reflex in the diode gap

A Long-Pulse Generator Based on Tesla Transformer and Pulse-Forming Network

Abstract: An approach for producing a long pulse up to 100 ns is presented. The generator based on this approach consists of a Tesla transformer and a set of pulse-forming networks (PFNs). The Tesla transformer is used to charge pulse-forming lines (PFLs) and PFNs which are in parallel. When the voltage increases to a certain value, the main switch will close, and the PFLs and PFNs will discharge rapidly to the load. Therefore, a high-voltage long pulse is formed on the load. The amplitude of this pulse is dependent only on the charging voltage and the matching state between the load and the PFL (PFN). The pulsewidth is determined by the transmission time of the PFL and PFN. The rise time is determined by the working state of the main switch and the impedance of the PFL and is independent of the parameters of the PFN. The PFN is multistage and assembled in series. The single-stage PFN is formed with ceramic capacitors placed between two unclosed annular plates. The total series impedance is equal to the sum of every single-stage PFN's impedance. A nine-stage PFN is used in the generator, and the total impedance is 40 Ω. Experimental results show that a high voltage of an amplitude of 300 kV, current of 6.9 kA, and duration of 110 ns is obtained at a repetition rate of 10 Hz, with a rise time of approximately 7 ns.

Propagation of neutralized plasma beams

Abstract: Beams of neutralized plasma will cross a transverse magnetic field, magnetized plasma, and neutral gas, by a combination of single particle and collective‐plasma processes. At low density the beam will deflect; at higher density the beam will exhibit undeflected motion by the E×B drift or diamagnetic (high‐beta) exclusion of the magnetic field. In the high‐beta regime, where β>1 (β is the ratio of plasma‐beam energy density to magnetic field energy density), beam magnetization occurs on a time scale orders of magnitude faster than the classical Spitzer time scale. Recent studies of fast magnetization suggest that transport processes in large ion gyroradius beams, y/ρi 1, where y and ρi are the beam transverse width and ion gyroradius, respectively. Although quantitative aspects of the small gyroradius propagation physics theory are still valid, most notably the E×B drift, much work remains ...

Experimental study of a plasma-filled backward wave oscillator

Abstract: We present experimental studies of a plasma-filled X-band backward wave oscillator (BWO). Depending on the background gas pressure, microwave frequency upshifts of up to 1 GHz appeared along with an enhancement by a factor of 7 in the total microwave power emission. The bandwidth of the microwave emission increased from ≤0.5 GHz to 2 GHz when the BWO was working at the RF power enhancement pressure region. The RF power enhancement appeared over a much wider pressure range in a high beam current case (10–100 mT for 3 kA) as compared to a lower beam case (80–115 mT for 1.6 kA). The plasma-filled BWO has higher power output compared to the vacuum BWO over a broader region of magnetic guide field strength. Trivelpiece-Gould modes (T-G modes) are observed with frequencies up to the background plasma frequency in a plasma-filled BWO. Mode competition between the Trivelpiece-Gould modes and the X-band TM 01 mode prevailed when the background plasma density was below 6×1011 cm−3. At a critical background plasma density of n cr ≅8×1011 cm−3 power enhancement appeared in both X-band and the T-G modes, with mode collaboration. Power enhancement of the S-band in this mode collaboration region reached up to 8 dB. Electric fields measured by Stark-effect method were as high as 34 kV/cm while BWO power level was 80 MW. These electric fields lasted throughout the high power microwave pulse.